A new study by a team from the University of Pennsylvania and MIT suggests it will be easier for cities to reduce CO2 emissions coming from residential energy use rather than from local transportation. This reduction will happen mostly thanks to better building practices, not greater housing density. The study is published in the Journal of Planning Education and Research.

The study used a series of fixed-ratio projections and scenarios to explore the potential for local residential energy conservation mandates and compact growth programs to reduce locally-based CO2 emissions in eleven representative US metropolitan areas. The modeling showed that averaged across all eleven metros, residential energy conservation mandates could reduce residential CO2 emissions in 2030 by an average of 30% over and above 2010 levels. . . .

Guy [I have lots of experience designing/selling off-grid AE systems, some using EVs but don't own one. Local trips are by foot, bike and/or rapid transit].

The 'best' is the enemy of 'good enough'.Copper shot, not Silver bullets.

Of course, we need to do "all of the above" - construct more efficient buildings, use more renewable energy, and switch to EVs.

As one of the commenters on that article sort of pointed out, there's a law of diminishing returns in the pursuit of efficiency. I discovered this in shopping for a new sliding glass door. The best possible Milgard product, which is Energy Star rated, would be about $1200. Or I could go with an Alpen product (see http://thinkalpen.com) with at least double the R-value, etc., for about $4000. While Alpen's products look quite impressive, I simply can't justify paying that much money! Adding more solar panels or improving some of our wall insulation would be a better use of funds.

From the study,“Simply requiring newly built homes to be more energy efficient would reduce residential emissions by an average of 6% by 2030. But requiring existing homes to be retrofitted would yield a further 19% reduction of residential emission, on average, across the 11 cities.”

Improved conservation by retrofitting had the biggest impact, especially for communities that are not building many new housing.

For the San Diego area, much of our air pollution comes from Transportation. So improvement or reductions from Transportation will have a big impact.

Also from the study,“Los Angeles, by contrast, produces only 10.7 kilograms of carbon dioxide emissions per million BTU, making its energy use about one-third as carbon-intensive as that of Cleveland and Denver. Ultimately each metropolitan area, Hsu suggests, may have to find its own path toward a clean energy future.”

So again, improvements in the Transportation sector will have a more significant impact.

Won't work here. My heat is electric and my electricity is 95% hydro (four dams, one nuke, and lots of wind within 50 mi). The best way to reduce CO2 in the PNW is eliminate gasoline/diesel vehicles, especially heavy transport and off-road vehicles (trucks, boats, etc.).